"Trying to convince Kristin Ess to dye my tips fuchsia for tonight's book signing…" the Hills alum tweeted hours before debuting her new candy-colored 'do via Instagram. "My Little (pink) Pony!" she wrote along with the pic.

Pink-dyed ends aren't the star's first experimentation with bright hair color -- in July, she streaked pink, purple and blue shades throughout her blonde mane and in January, she accented her signature "fun bun" hairstyle with cotton candy pink.